Is it a bug in switch statement?

Question

Why do we get “it is ten” instead of “no match” when for $z assigned value 0? With other values except 10 it prints “no match”.

$z = 0;

switch($z) {
case ($z === 10):
echo "<br> it is ten";
break;
default:
echo "no match";
break;
}

Answer 1

Each case is compared for equality with the switch operand.

switch($a) {
case $b: // passes if $a == $b
}

So your question,
switch($z) {
case ($z === 10):
// passes if $z === ($z === 10)
}

Let me break that down

$z == ($z === 10)

0 == (0 === 10)

0 == 0

1 // passes

The correct program should be

$z = 0;

switch($z) {
case 10:
echo "<br> it is ten";
break;
default:
echo "no match";
break;
}

Which can be shortened to

$z = 0;
echo($z === 10 ? "<br> it is ten" : "no match");

Answer 2

Thank you for your answer, now I understand why it shows me this result. So in this case it is better to use elseif to avoid an incorrect result?

Answer 3

Vadims Lukjanskis You can just write case 10 instead of case ($z === 10)